1. Field of the Invention
The present invention relates to an information processing apparatus that selectively operates in one of a normal power mode and a power saving mode, a method for controlling the information processing apparatus, and a storage medium.
2. Description of the Related Art
To improve system reliability of an information processing system having a storage device, such as a hard disk drive (HDD), it is necessary to take an appropriate measure in case of a failure in the storage device.
As an example of such a measure, there is a known technique in which an information processing system includes a plurality of storage devices to form a redundant array of inexpensive disks (RAID) system and perform a mirroring process. A mirroring process is a process in which when data is recorded in one storage device, a copy of the data is recorded in another storage device in case of a storage device failure.
If an error occurs in data stored in one of the plurality of storage devices in the information processing system where a mirroring process is performed, a restore process is executed. A restore process is a process in which when an error occurs in data stored in a storage device, data backed-up in another storage device is used to restore the data where the error has occurred.
If the data where the error has occurred cannot be restored even when the restore process is performed, the storage device itself needs to be replaced with a new one. After the storage device is replaced with a new storage device, it is necessary to execute a rebuild process to rebuild information in the new storage device. Japanese Patent Laid-Open No. 2006-221335 describes performing a rebuild process to rebuild information in a storage device.
In recent years, an information processing apparatus which has two different power modes to achieve lower power consumption during standby has been known. The two power modes include a normal power mode for normal operation, and a power saving mode which allows lower power consumption than that in the normal power mode.
When this information processing apparatus switches to the power saving mode, the supply of power to a predetermined module including a main control unit, the predetermined module being one of a plurality of modules constituting the information processing apparatus, is stopped. This makes it possible to reduce the total power consumption of the information processing apparatus.
However, to perform the rebuild process in the related art, it is necessary that the information processing apparatus be operating in the normal power mode (not in the power saving mode). This is because the main control unit, which is not supplied with power while the information processing apparatus is operating in the power saving mode, executes the rebuild process in the related art.
Since the information processing apparatus operates in the normal power mode during execution of the rebuild process, a larger amount of power continues to be consumed as compared to the case where the information processing apparatus operates in the power saving mode. In particular, when the rebuild process is performed for a storage device where data of several tens of gigabytes is stored, it may take several hours to complete the process. As a result, the problem of increased power consumption becomes more significant.
If it is made possible to execute the rebuild process for a storage device while the information processing apparatus is operating in the power saving mode, the following problem may arise. That is, when the power saving mode is entered, the supply of power to the main control unit of the information processing apparatus is stopped. Therefore, even if an error occurs during execution of the rebuild process, it is not possible to detect the occurrence of the error. As a result, even if the rebuild process does not complete normally, the storage device is left as it is.
Alternatively, the information processing apparatus may be made to return from the power saving mode to the normal power mode, every time the rebuild process completes. However, it is possible in this case that the information processing apparatus returns to the normal power mode even when the rebuild process has been successful. If the rebuild process has been successful, there is no need to immediately notify the main control unit of the success. However, since the information processing apparatus returns to the normal power mode, power is consumed unnecessarily.